Achilles tendon ossification after treatment with acitretin.

Achilles tendon ossifications are rare. Usually they develop after surgery or trauma. The present case report illustrates a severe and tender Achilles tendon ossification of 10 cm in length a few months after treatment with acitretin for lichen ruber. With discontinuation of acitretin therapy, regression of pain was achieved but the ossification was irreversible. This case should raise awareness for possible and severe calcifications in the use of retinoid therapy.